include/net/netfilter/nf_conntrack_rtsp.h

/*
 * RTSP extension for IP connection tracking.
 * (C) 2003 by Tom Marshall <tmarshall at real.com>
 * based on ip_conntrack_irc.h
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 *
 * 2013-03-04: Il'inykh Sergey <sergeyi at inango-sw.com>. Inango Systems Ltd
 *	- conditional compilation for kernel 3.7
 *	- port mapping improvements
*/
#ifndef _IP_CONNTRACK_RTSP_H
#define _IP_CONNTRACK_RTSP_H

#include <linux/version.h>

//#define IP_NF_RTSP_DEBUG 1
#define IP_NF_RTSP_VERSION "0.7"

#ifdef __KERNEL__
/* port block types */
typedef enum {
    pb_single,  /* client_port=x */
    pb_range,   /* client_port=x-y */
    pb_discon   /* client_port=x/y (rtspbis) */
} portblock_t;

/* We record seq number and length of rtsp headers here, all in host order. */

/*
 * This structure is per expected connection.  It is a member of struct
 * ip_conntrack_expect.  The TCP SEQ for the conntrack expect is stored
 * there and we are expected to only store the length of the data which
 * needs replaced.  If a packet contains multiple RTSP messages, we create
 * one expected connection per message.
 *
 * We use these variables to mark the entire header block.  This may seem
 * like overkill, but the nature of RTSP requires it.  A header may appear
 * multiple times in a message.  We must treat two Transport headers the
 * same as one Transport header with two entries.
 */
struct ip_ct_rtsp_expect
{
    u_int32_t   len;        /* length of header block */
    portblock_t pbtype;     /* Type of port block that was requested */
    u_int16_t   loport;     /* Port that was requested, low or first */
    u_int16_t   hiport;     /* Port that was requested, high or second */
#if 0
    uint        method;     /* RTSP method */
    uint        cseq;       /* CSeq from request */
#endif
};

extern unsigned int (*nf_nat_rtsp_hook)(struct sk_buff *skb,
					enum ip_conntrack_info ctinfo,
#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,7,0)
					unsigned int protoff,
#endif
					unsigned int matchoff,
					unsigned int matchlen,
					struct ip_ct_rtsp_expect *prtspexp,
					struct nf_conntrack_expect *rtp_exp,
					struct nf_conntrack_expect *rtcp_exp);

#define RTSP_PORT   554

#endif /* __KERNEL__ */

#endif /* _IP_CONNTRACK_RTSP_H */